I don't know ForTRAN

This repository will contain chunks of fortran code that will be useful while writing codes.

Here are some useful functions / pieces of code that you would find helpful while using these commands on your projects. Please report any issues / comments on issues section of this repository.

Functions

Check if file exists

Check if a file exists

! DEFINE FEXISTS as LOGICAL
LOGICAL FEXISTS 
INQUIRE (FILE = 'Filename.DAT', EXIST = FEXISTS)
  IF( FEXISTS )THEN

  ELSE

  ENDIF

Conditional debugging in FORTRAN

While debugging the code, we might be interested to debug line by line when certain conditions is met. To do that in visual studio, we need to first create a break point and right click on the break point. The following options will pop up:

Then we can click on Condition and then insert the condition as if we were writing an if statement.

Open and close files in FORTRAN

To open files in FORTRAN simply use:

OPEN(7, FILE = 'hello.txt', STATUS = 'UNKNOWN')

where 7 = the unique number assigned to the file that is being opened.

To close the files we can simply use :

CLOSE(7)

If we want to delete the file then we can use CLOSE(7, STATUS = 'DELETE')

Append files in FORTRAN

To do the appends in FORTRAN we could do something like:

OPEN(95,FILE=OUTDIR//'*.OUT',POSITION='APPEND',STATUS='OLD',  FORM='BINARY')
! Some code 
CLOSE(95) 

In the above code 95 is just used arbitrarily.

Allocatable arrays in FORTRAN 90

In FORTRAN 90, one can assign allocatable arrays with the syntax as follows:

REAL,ALLOCATABLE,DIMENSION(:)::RSSBCW
REAL, ALLOCATABLE, DIMENSION(:,:):: TESTDF

In the above example, RSSBCW is a 1-D vector whereas TESTDF is a 2 dimensional array.

Using modules

A simple module structure would look something like:

MODULE COMPUTATION

! Assign some variables 
SAVE

! Add pieces of code / Functions 

END MODULE COMPUTATION

Now, while referring to the main program, you can use a simple syntax as follows:

USE COMPUTATION

After that we would be able to access all the code written in the modules. So, I think it is very useful way to write bunch of functions and subroutines into one program.